#include <machine/asm.h>

#ifndef _RUMPKERNEL
STRONG_ALIAS(__ffssi2,ffs)
#endif
#if (defined(_ARM_ARCH_5) && !defined(__thumb__)) || defined(_ARM_ARCH_T2)
#if defined(_ARM_ARCH_T2)
ENTRY(ffs)
#else
ARM_ENTRY(ffs)
#endif
	/* (X & -X) gives LSB or zero.  */
 	neg	r1, r0
 	and	r0, r0, r1
	clz	r0, r0
	rsb	r0, r0, #32
	RET
END(ffs)
#else
ARM_ENTRY(ffs)
	/* Standard trick to isolate bottom bit in r0 or 0 if r0 = 0 on entry */
 	neg     r1, r0
 	ands    r0, r0, r1
	/*
	 * now r0 has at most one set bit, call this X
	 * if X = 0, all further instructions are skipped
	 */
	adrne   r2, .L_ffs_table
	orrne   r0, r0, r0, lsl #4  /* r0 = X * 0x11 */ 
	orrne   r0, r0, r0, lsl #6  /* r0 = X * 0x451 */
	rsbne   r0, r0, r0, lsl #16 /* r0 = X * 0x0450fbaf */
              
	/* now lookup in table indexed on top 6 bits of r0 */
	ldrbne  r0, [r2, r0, lsr #26]

        RET
.text;
.type .L_ffs_table, _ASM_TYPE_OBJECT;
.L_ffs_table:
/*               0   1   2   3   4   5   6   7           */
	.byte	 0,  1,  2, 13,  3,  7,  0, 14  /*  0- 7 */
	.byte	 4,  0,  8,  0,  0,  0,  0, 15  /*  8-15 */
	.byte	11,  5,  0,  0,  9,  0,  0, 26  /* 16-23 */
	.byte	 0,  0,  0,  0,  0, 22, 28, 16  /* 24-31 */
	.byte	32, 12,  6,  0,  0,  0,  0,  0	/* 32-39 */
	.byte	10,  0,  0, 25,  0,  0, 21, 27  /* 40-47 */
	.byte	31,  0,  0,  0,  0, 24,  0, 20  /* 48-55 */
	.byte   30,  0, 23, 19, 29, 18, 17,  0  /* 56-63 */
END(ffs)
#endif
